Methods and apparatus to reduce inrush current in universal serial bus circuits and systems

ABSTRACT

Methods, apparatus, systems and articles of manufacture are disclosed including a capacitor, located in a universal serial bus schematic. The methods, apparatus, systems and articles of manufacture include a controller, include a controller including a state machine and a control signal generator, wherein the controller is configured to be coupled to a connector and to a power supply, the state machine is configured to determine a state of the connector, and the control signal generator is configured to, in response to an indication of a device not connected to the connector, generate a signal to indicate to the power supply to charge a capacitor to a threshold voltage, and wherein the control signal generator is further configured to generate the signal until a second state.

CROSS-REFERENCED TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 16/263,668 filed on Jan. 31, 2019, which is herebyincorporated herein in its entirety.

FIELD OF THE DISCLOSURE

This disclosure relates generally to Universal Serial Bus systems, and,more particularly, to methods and apparatus to reduce inrush current inUniversal Serial Bus circuits and systems.

BACKGROUND

Universal Serial Bus (USB) systems include Universal Serial Bus Type-A(USB-A) and Universal Serial Bus Type-C (USB-C), each of which has astandard connector. USB-C compatible systems and devices (e.g., personalcomputers, docks, monitors) include a female and/or male connectorstructured differently than a USB-A female and/or male connector. Thefemale and/or male connectors in USB-C compatible systems and devicesare structured to be utilized by different electrical connectionprotocols than female and/or male connectors in USB-A compatiblesystems.

SUMMARY

The methods, apparatus, systems and articles of manufacture include acontroller including a state machine and a control signal generator,wherein the controller is configured to be coupled to a connector and toa power supply, the state machine is configured to determine a state ofthe connector, and the control signal generator is configured to, inresponse to an indication of a device not connected to the connector,generate a signal to indicate to the power supply to charge a capacitorto a threshold voltage, and wherein the control signal generator isfurther configured to generate the signal until a second state.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustrating a USB-C system including a USB-Cfemale connector coupled to a USB-A device through an adapter.

FIG. 2 is a schematic illustrating a USB-C system including a USB-Cfemale connector coupled to a USB-A device through an adapter, furtherincluding two blocking transistors.

FIG. 3 is a schematic illustrating a USB-C system coupled to a USB-Asystem.

FIG. 4 is a block diagram showing additional detail of an examplecontroller that may be used in combination the USB-C system of FIG. 3 .

FIG. 5 is a schematic illustrating an example dual-port device coupledto an example controller to control an example variable power supply.

FIG. 6 is a graphical illustration of various signals of the examplesystem of FIG. 3 during operation.

FIG. 7 is a state diagram representative of example operating states inwhich the controller of FIG. 3, 4 , or 5 may operate.

FIG. 8 is a flowchart representative of machine readable instructionsthat may be executed to implement the controller of FIGS. 3-5 .

The figures are not to scale. In general, the same reference numberswill be used throughout the drawing(s) and accompanying writtendescription to refer to the same or like parts.

DETAILED DESCRIPTION

Universal Serial Bus (USB) is a common interface established for cables,connectors, protocols for connection, communication, and power supply.The USB standard includes several standard connectors (e.g., male andfemale connectors) such as Universal Serial Bus Type-A (USB-A) andUniversal Serial Bus Type-C (USB-C).

The USB-A standard allows for a male connector to plug into a hostdevice (e.g., desktop computer, laptop, dock). According to the USB-Astandard, the host device (e.g., desktop computer, laptop, dock, dock)is a device to which USB-A compatible devices can connect. The USB-Acompatible devices may supply power (e.g., a USB-A source) or consumepower (e.g., a USB-A sink device). Generally, the USB-A standardsupports the technical specifications such as Universal Serial Bus 1.0(USB 1.0), Universal Serial Bus 1.1 (USB 1.1), Universal Serial Bus 2.0(USB 2.0), Universal Serial Bus 3.0 (USB 3.0). The specificationssupported by USB-A (e.g., USB 1.0, USB 1.1, USB 2.0, and USB 3.0)describe varying data and/or power transfer limits. Electricalspecifications and standards supported by the USB-A standard (e.g.,USB-A female and/or male connectors) include a main voltage bus(V_(BUS_A)) in the female connector. The main voltage bus (V_(BUS_A))may also be included on the male connector. For a USB-A source, the mainvoltage bus (V_(BUS_A)) includes a voltage potential of five volts. Anelectrical standard supported by the USB-A standard (e.g., USB-Aconnectors) includes a voltage potential across V_(BUS_A) while a USB-Asource (e.g., computer, laptop, dock) is plugged in.

The USB-C standard allows host devices (e.g., desktops, computers,laptops, docks,) to act as a host or a peripheral device. Moreover, aUSB-C compatible device may supply power (e.g., a USB-C source), consumepower (e.g., a USB-C sink), or supply and/or consume power (e.g., aUSB-C Dual Role Power (DRP) device). Example USB-C DRP devices includedocks, monitors, personal computers, cellular phones, or any otherdevice capable of consuming and supplying power. The USB-C standardincludes full duplex (e.g., ability simultaneously communicatehost-to-device or device-to-host) connection capabilities. A full duplexconnector is a connector that allows for the transmission of data in twodirections, simultaneously. The full duplex USB-C connector enablescompatible electronic devices to cross talk, supply power, consumepower, etc., simultaneously.

Additionally, the USB-C standard supports the technical specificationssupported by USB-A, along with the Universal Serial Bus 3.1 (USB 3.1)and Universal Serial Bus Power Delivery (USB PD) specifications. The USB3.1 specification supports a higher maximum data transfer rate (e.g.,capable of transferring data at 20 Gbit/s) than supported by previousspecifications (e.g., USB 1.0, USB 1.1, USB 2.0, and USB 3.0). The USBPD specification supported by the USB-C standard allows for higher power(e.g., up to 100 W) transfer limits than allowed by previousspecifications (e.g., USB 1.0, USB 1.1, USB 2.0, and USB 3.0). The USB-Cstandard supports all legacy specifications supported by the USB-Astandard.

Electrical specifications and standards supported by the USB-C standard(e.g., USB-C connectors) include a main voltage bus (V_(BUS_C)) in thefemale connector. The main voltage bus (V_(BUS_C)) may also be includedon the male connector. For USB-C source and/or DRP devices, the mainvoltage bus (V_(BUS_C)) includes a voltage potential of zero volts. Anelectrical standard supported by the USB-C standard (e.g., USB-Cconnectors) includes zero voltage potential across (V_(BUS_C)) in themale connector while a USB-C device is unattached (e.g., a cold socketwhen there is no connected device). The USB-C standard does not enablevoltage across its respective main voltage bus (e.g., no voltagepotential across (V_(BUS_C)) due to standards set by the USB-Cmanufacturers.

In comparison to the USB-A standard, the USB-C standard includesphysically smaller male and female connectors. For example, the USB-Cconnector is about 8.25 millimeters in width and 2.4 millimeters inheight. Whereas, the USB-A connector is about 12 millimeters in widthand 4.5 millimeters in height. The USB-C standard can support the legacyspecifications of the USB-A standard (e.g., USB 1.0, USB 1.1, USB 2.0,and USB 3.0), and therefore, there are often instances of USB-A to USB-Cconnections. USB-A to USB-C adapters are used to link a USB-A compatibledevice with a USB-C compatible device. Typically, the USB-A to USB-Cadapter includes a USB-A female connector and a USB-C male connector. Inthis manner, the USB-A female connector of the adapter can receive theUSB-A male connector from a USB-A compatible device (e.g., a USB-Asource or sink), and the USB-C male connector of the adapter can pluginto the USB-C female connector of the USB-C compatible device (e.g.,device housing the USB-C female connector).

Due to the different electrical protocols for USB-A and USB-C devices(e.g., different regulations for the respective main voltage busses),problems can arise when connecting a USB-A compatible device to USB-Ccompatible device. For example, if a USB-A compatible device supplyingpower (e.g., USB-A source) connects to a USB-C compatible device (e.g.,through utilizing a USB-A to USB-C adapter such as a USB-A to USB-Ccable), a initial inrush of current may occur. The initial inrush ofcurrent occurs due to the different voltage potentials at the USB-Acompatible device voltage bus (e.g., (V_(BUS_A)) and USB-C compatibledevice voltage bus (e.g., (V_(BUS_C)). Since the voltage across thevoltage bus in the USB-C connector (V_(BUS_C)) is close to zero, theconnector with the higher V_(BUS) voltage (e.g., USB-A male connector)will drive current into the other connector (e.g., USB-C femaleconnector). For example, if a USB-A compatible cellular phone acts as aUSB-A source, the USB-A compatible cellular phone may have a five-voltpotential on the main voltage bus (e.g., (V_(BUS_A)) ). Furthermore, ifthe USB-A compatible cellular phone is connected to USB-C compatibledevice (e.g., a USB-C compatible device including a zero-volt potentialon the main voltage bus (V_(BUS_C)) ), utilizing a USB-A to USB-Cadapter, the five-volt potential on the USB-A compatible cellular phonemain voltage bus (e.g., (V_(BUS_A)) ) may cause inrush current to bedriven in to the USB-C comparable device. When inrush current flows intoa connector that should not have current flowing into it, the USB-Acompatible device or USB-C compatible device may be damaged.

Prior attempts to reduce the amount of initial inrush current flowinginto a connector that should not have current flowing into it includeadding a transistor (e.g., a switch) on the USB-C compatible device sideconnector. This transistor is designed to block the initial inrush ofcurrent that may occur when plugging a USB-A compatible device (e.g.,USB-A source) into a USB-C compatible device. For example, thetransistor may be turned off (e.g., not conduct) when anticipating aUSB-A device to be plugged in to block the initial inrush of current.Alternatively, prior attempts to reduce the amount of initial inrushcurrent into a USB-C device include utilizing a voltage bus capacitorcoupled to the voltage bus in the USB-C device (e.g., voltage buscapacitor coupled to the voltage bus in the female connector of a USB-Ccompatible device). The voltage bus capacitor is designed to store thecharge resulting from the initial inrush of current. Due to devicestandards (e.g., standards initiated by USB-C manufacturers), thevoltage bus capacitor is minimized to a value that is incapable ofstoring all of the charge resulting from the initial inrush of current.

FIG. 1 is a schematic 100 illustrating a USB-C female connector 102coupled to a USB-A device 104 through an USB-A to USB-C adapter 103. TheUSB-C schematic 100 includes a voltage bus capacitor 106 and a blockingtransistor 108. The voltage bus capacitor 106 is coupled between theground node 110 and a source terminal 112 of the blocking transistor108. Furthermore, the USB-C schematic 100 includes a system capacitor114. The system capacitor 114 is coupled between the ground node 110 anda drain terminal 116 of the blocking transistor 108.

In the illustration depicted in FIG. 1 , the USB-C female connector 102is connected to the example USB-A device 104. The USB-A device 104 isconnected to the USB-C female connector 102 using a USB-A to USB type Cadapter 103.

The example USB-A device 104 utilizes the USB-A standards (e.g., USB-Aelectrical characteristics and physical connections) of operation. Whena USB-A device 104 is plugged into the USB-C female connector 102, aninitial inrush of current (Current A) conducts into the USB-C femaleconnector 102. The initial inrush of current (Current A) occurs when theUSB-A device 104 supplies power (e.g., acts as a USB-A source) to theUSB-C female connector 102, or when the USB-A device 104 includes avoltage potential (e.g., five volts) across the main voltage bus (e.g.,(V_(BUS_A)) and the USB-C female connector 102 includes zero voltagepotential across its respective main voltage bus (e.g., (V_(BUS_C)) ornode 120).

The voltage bus capacitor 106 is a large (e.g., ten microfarad)capacitor that stores energy proportional to the current conductingthrough it (Current B). The current (e.g., Current B) conducting throughthe voltage bus capacitor 106 is generated from the initial inrush ofcurrent (Current A).

The blocking transistor 108 in FIG. 1 is an n-channelmetal-oxide-semiconductor (NMOS) field-effect transistor. The blockingtransistor 108 includes a source terminal 112, a drain terminal 116 anda parasitic body diode 118.

The ground node 110 provides a reference voltage for the USB-C schematic100. In the illustration depicted in FIG. 1 the ground node 110 is achassis ground.

The system capacitor 114 is relatively larger than the voltage buscapacitor 106 (e.g., a six hundred microfarad capacitor). When a USB-Adevice 104 is plugged into the USB-C female connector 102, current,Current C, conducts through the parasitic body diode 118 of the blockingtransistor 108.

In the illustration depicted in FIG. 1 , the USB-A device 104 is pluggedinto the USB-C female connector 102. Due to a voltage potential existingat the USB-A device 104 (e.g., a five-volt potential across (V_(BUS_A)),an initial inrush of current conducts into the USB-C female connector102 (Current A). The initial inrush of current (Current A) conductsthrough the parasitic body diode 118 (e.g., Current C) of the exampleblocking transistor 108. In this scenario, the parasitic body diode 118conducts current because the voltage drop across the anode terminal (thesource terminal 112) and the cathode terminal (the drain terminal 116)exceeds the conduction threshold of the parasitic body diode 118 (e.g.,0.7 volts). When this occurs, the USB-A device 104 is conducting current(Current C) through the parasitic body diode 118 to the system capacitor114. The current conducting through the parasitic body diode 118(Current C) may cause damage to the USB-C compatible device (e.g., thedevice housing the USB-C female connector 102) and/or the USB-A device104.

Prior attempts to account for the current flowing through the inherentparasitic body diode of the transistor include adding a secondtransistor in series with the first transistor. In these attempts, thesecond transistor includes a parasitic body diode that conducts currentwhen the polarity of the voltage drop across the parasitic body diode itopposite of the polarity of the voltage drop across the parasitic bodydiode in the first transistor. This attempt is costly to implementbecause this implementation uses twice the number of transistors.

FIG. 2 is a schematic 200 illustrating a USB-C female connector 202coupled to a USB-A device 204 through a USB-A to USB-C adapter 203,further including two blocking transistors 207, 208. The USB-C schematic200 includes a voltage bus capacitor 206 and two blocking transistors207, 208. The blocking transistors 207, 208 are n-channelmetal-oxide-semiconductor (NMOS) field-effect transistors. The voltagebus capacitor 206 is coupled to the ground node 210 and the sourceterminal 212 of the blocking transistor 207. Furthermore, the USB-Cschematic 200 includes a system capacitor 214. The system capacitor 214is coupled between the ground node 210 and a source terminal 216 of theblocking transistor 208.

In the illustration depicted in FIG. 2 , the USB-C female connector 202is connected to the example USB-A device 204. The USB-A device 204 isconnected to the USB-C female connector 202 using a USB-A to USB type Cadapter 203.

The example USB-A device 204 utilizes the USB-A standards (e.g., USB-Aelectrical characteristics and physical connections) of operation. Whena USB -A device 204 is plugged into the USB-C female connector 202, aninitial inrush of current (Current A) conducts into the USB-C femaleconnector 202. The initial inrush of current (Current A) occurs when theUSB-A device 204 supplies power (e.g., acts as a USB-A source) to theUSB-C female connector 202, or when the USB-A device 204 includes avoltage potential (e.g., five volts) across the main voltage bus (e.g.,V_(BUS_A)) and the USB-C female connector 102 includes zero voltagepotential across its respective main voltage bus (e.g., (V_(BUS_C)) ornode 220).

The voltage bus capacitor 206 is a large (e.g., ten-microfarad)capacitor. The voltage bus capacitor 206 stores energy proportional tothe current conducting through it (Current B). The current (e.g.,Current B) conducting through the voltage bus capacitor 206 is generatedfrom the initial inrush of current (Current A).

The blocking transistor 207 in FIG. 2 is an n-channelmetal-oxide-semiconductor (NMOS) field-effect transistor. The blockingtransistor 207 includes the source terminal 212, a drain terminal 213and a parasitic body diode 218. The blocking transistor 208 of FIG. 2includes a drain terminal 217, the source terminal 216 and a parasiticbody diode 219.

The ground node 210 provides a reference voltage for the USB-C schematic200. In the illustration depicted in FIG. 2 the ground node 210 is achassis ground.

The system capacitor 214 is relatively larger than the voltage buscapacitor 214 (e.g., a six hundred-microfarad capacitor). When a USB-Adevice 204 is plugged into the USB-C female connector 202, current,Current C, conducts through the parasitic body diode 218 of the blockingtransistor 207.

In the illustration depicted in FIG. 2 , the USB-A device 204 is pluggedinto the USB-C female connector 202. Due to a voltage potential existingat the USB-A device 204, an initial inrush of current (Current A)conducts into the USB-C female connector 202. The initial inrush ofcurrent (Current A) conducts through the parasitic body diode 218 of theexample blocking transistor 207 (e.g., Current C). In the illustrationdepicted in FIG. 2 , the current (Current C) conducting through theparasitic body diode 218 is blocked by the parasitic body diode 219. Theillustration depicted in FIG. 2 utilizes two transistors (e.g., blockingtransistors 207 and 208) to block the initial inrush of current from theUSB-A device 204. The illustration depicted in FIG. 2 includes twice theamount of blocking transistors used in examples disclosed herein.

Examples disclosed herein allow for the protection of USB devices whenconnecting a USB-A compatible device to a USB-C compatible device.Furthermore, examples disclosed herein include utilizing a singletransistor to block the initial inrush of current when connecting aUSB-A compatible device to a USB-C compatible device. Examples disclosedherein include utilizing the system side capacitor (e.g., the largecapacitance on the system side of the transistor in a USB-C device) toreverse bias the parasitic body diode of the blocking transistor.

Examples disclosed herein include the ability to pre-charge the systemside capacitor (e.g., the large capacitance on the system side of thetransistor in a USB-C device). In examples disclosed herein, the systemside capacitor (e.g., the large capacitance on the system side of thetransistor in a USB-C device) is pre-charged to a voltage large enoughto reverse bias the parasitic body diode in the transistor. Someexamples include pre-charging the system side capacitance (e.g., thelarge capacitance on the system side of the transistor in a USB-Cdevice) to five volts; however, examples disclosed herein includepre-charging the system side capacitor to any numerical voltage value.

Examples disclosed herein include preventing inrush current that occurswhen attaching (e.g., connecting) a USB-A host (e.g., USB-A source)and/or a USB-A device (e.g., USB-A sink) into a USB-C dual role powerdevice (DRP). Examples disclosed herein include verifying the state ofthe USB-A host (e.g., USB-A source) and/or the USB-A device (e.g.,(V_(BUS_A)) sink) and adjusting the power flow in the USB-C dual rolepower (DRP) device to accommodate the state of the USB-A host (e.g.,USB-A source) and/or a USB-A device (e.g., USB-A sink). Examplesdisclosed herein are not limited to preventing inrush current thatoccurs when attaching a USB-A standard device (e.g., USB-A host and/orUSB-A device) into a USB-C DRP device, and in fact, include preventinginrush current that may occur when attaching any other device (e.g.,USB-C Standard Device) into a USB-C DRP device. For example, the inrushcurrent that may occur when attaching (e.g., connecting) a USB-C DRPdevice to a USB-C DRP device may be prevented in examples disclosedherein.

Examples disclosed herein include preventing the initial inrush ofcurrent in a USB-C device that may occur when verifying and/or adjustingfor the state of a connected USB-A host (e.g., USB-A source), a USB-Adevice (e.g., USB-A sink), a USB-C DRP device, or any other USB capabledevice and/or host.

FIG. 3 is a schematic 300 illustrating a USB-C system 301 coupled to aUSB-A system 303. The example USB-C system 301 includes the componentsand/or devices housed by a USB-C compatible device (e.g., dock,monitor). Example components and/or devices included in the USB-C system301 include an example voltage bus capacitor 316, an example blockingtransistor 306, an example system capacitor 318, an example controller320, and an example universal serial bus type-C female connector 302(USB-C female connector 302). In other examples disclosed herein, theUSB-C female connector 302 may be a universal serial bus type-cconnector or any suitable universal serial bus connector. Additionally,in examples disclosed herein, the USB-C female connector 302 is auniversal serial bus type-c power delivery compatible connector that iscompatible with universal serial bus type-c power delivery applications.The example USB-A system 303 includes the components and/or deviceshoused by an example universal serial bus type-A device 304 (USB-Adevice 304), along with an example universal serial bus type-a touniversal serial bus type-c adapter 305 (USB-A to USB-C adapter 305). Inother examples disclosed herein, the USB-A device 304 may be a universalserial bus type-A host, a universal serial bus type-C DRP device, or anyother universal serial bus compatible device.

The USB-C system 301 may be located in a universal serial bus compatibledevice such as a host device (e.g., personal computer, laptop, dock);however, the USB-C system 301 may be located in other devices as well(e.g., peripheral devices). In the USB-C system 301, the voltage buscapacitor 316 is coupled to the example ground node 328 and the examplecurrent terminal 310 (e.g., source terminal) of the blocking transistor306. The system capacitor 318 is coupled to the ground node 328 and thecurrent terminal 312 (e.g., drain terminal) of the blocking transistor306. Additionally, the power supply 322 is coupled to the currentterminal 312 (e.g., drain terminal) and the system capacitor 318. Anexample controller 320 is coupled to the power supply 322, the blockingtransistor 306, and the example USB-C female connector 302.

In the example depicted in FIG. 3 , the USB-C female connector 302 isconnected to the example USB-A device 304 through the example USB-A toUSB-C adapter 305. Examples disclosed herein are not limited to theUSB-A device 304, and in fact, some examples disclosed herein include asecond USB-C compatible device connected to the USB-C female connector302. The USB-C female connector 302 includes full duplex (e.g., abilitysimultaneously communicate host-to-device or device-to-host) connectioncapabilities. The full duplex USB-C connector (e.g., the USB-C femaleconnector 302) enables compatible electronic devices to cross talk,supply power, consume power, etc., simultaneously. The device housingthe USB-C system 301 may supply power and/or consume power to a deviceconnected to the USB-C female connector 302.

Additionally, the USB-C female connector 302 may support thespecifications supported by USB-A (e.g., USB 1.0, USB 1.1, USB 2.0, USB3.0), along with the Universal Serial Bus 3.1 (USB 3.1) and UniversalSerial Bus Power Delivery specifications. The USB-C female connector 302may support all legacy specifications supported by the USB-A standard.Furthermore, the USB-C female connector 302 includes a USB-C mainvoltage bus 324 (e.g., (V_(BUS_C)) ). Ideally, the USB-C main voltagebus 324 (e.g., (V_(BUS_C)) has a zero-voltage potential while a deviceis anticipated to be plugged in.

The example USB-A device 304 is connected to the USB-C female connector302 using the USB-A to USB-C adapter 305. In some examples disclosedherein, the USB-A device 304 may be a USB-C compatible device, and thus,a USB-C compatible device may be connected to the USB-C female connector302 (e.g., attaching a male USB-C connector from a USB-C compatibledevice into the USB-C female connector 302 of FIG. 3 ).

In the example illustrated in FIG. 3 , the USB-A device 304 is coupledto the USB-C female connector 302 to consume power from the devicehousing the USB-C system 301. Other examples disclosed herein includecoupling the USB-A device 304 to the USB-C female connector 302 tosupply power to the device housing the USB-C system 301. The exampleUSB-A device 304 utilizes the USB-A standards (e.g., USB-A electricalcharacteristics and physical connections) of operation. In some examplesdisclosed herein, the USB-A device 304 may supply power to a dock,monitor, or personal computer (e.g., the dock, monitor, or personalcomputer includes the USB-C female connector 302). Other examplesdisclosed herein include a USB-A device 304 to connect and/orcommunicate with a USB-type C compatible device (e.g., dock, monitor, orpersonal computer). Additionally, some examples disclosed herein includea USB-C compatible device to connect and/or communicate with anotherUSB-C compatible device (e.g., dock, monitor, or personal computer).

The example blocking transistor 306 is an n-channelmetal-oxide-semiconductor field-effect transistor (NMOS). In otherexamples, the blocking transistor 306 may be an p-channelmetal-oxide-semiconductor field-effect transistor (PMOS) or any otherswitching device. The blocking transistor 306 includes a gate terminal308, a current terminal 310 (source terminal), a current terminal 312(e.g., drain terminal), and a parasitic body diode 314. In the exampledepicted in FIG. 3 , the blocking transistor 306 includes a gateterminal 308 coupled to a controller 320.

The example gate terminal 308 of the blocking transistor 306 receives aninput signal from the example controller 320. The input signal receivedat the gate terminal 308 of the blocking transistor 306 may be a pulsewidth modulation (PWM) signal. The PWM signal is a periodic signalhaving a frequency with a respective on-time and off time.

The example current terminal 310 (e.g., source terminal) of the blockingtransistor 306 is coupled to the voltage bus capacitor 316 and the USB-Cfemale connector 302 (e.g., the USB-C main voltage bus 324). The currentterminal 312 (e.g., drain terminal) of the blocking transistor 306 iscoupled to the example system capacitor 318 and the power supply 322.

Additionally, the blocking transistor 306 includes an example parasiticbody diode 314. The parasitic body diode 314 is a parasitic diode thatconducts current when a voltage drop between the anode (e.g., currentterminal 310) and the cathode (e.g., current terminal 312) exceeds aconduction threshold. In some examples, the conduction threshold is 0.7volts; however, the conduction threshold amount is not limited to anyvalue disclosed herein. The parasitic body diode 314 is an inherentresult from manufacturing the example blocking transistor 306. When theblocking transistor 306 is conducting (e.g., a turn on signal has beensent by the controller 320) the current carried by the parasitic bodydiode (Current C) is negligible. For example, when the blockingtransistor 306 is conducting (e.g., a turn on signal has been sent bythe controller 320), the current conducting through the current terminal310 (e.g., source terminal) to the current terminal 312 (e.g., drainterminal) may be three amperes, and the current conducting through theparasitic body diode 314 may be one microampere. Other examples includewhen the blocking transistor 306 is not conducting (e.g., a turn-offsignal has been sent by the controller 320). In these examples, thecurrent conducting through the current terminal 310 (e.g., sourceterminal) to the current terminal 312 (e.g., drain terminal) is zeroamperes, and the current conducting through the parasitic body diode 314may be one microampere. Other examples disclosed herein include acurrent conducting through the parasitic body diode 314, while theblocking transistor 306 is conducting or not conducting, of anynumerical ampere value (e.g., one ampere, 5 amperes, 10 amperes). Theconduction of current through the parasitic body diode 314 when theblocking transistor 306 is not conducting may cause damage to the USB-Cdevice (e.g., the device that includes the USB-C system 301), the USB-Adevice 304, or any other USB device attached to the USB-C femaleconnector 302 (e.g., a USB-C compatible device).

The example voltage bus capacitor 316 is a two terminal electricalcomponent that stores energy in an electric field. In examples disclosedherein, the example voltage bus capacitor 316 includes a large (e.g.,ten-microfarad) capacitor. When a USB-A device 304 is plugged into theUSB-C female connector 302, an initial inrush of current (Current A)conducts into the USB_C female connector 302. In the example depicted inFIG. 3 , the initial inrush of current (Current A) occurs due to thedifference in voltage potential across the USB-A voltage bus (e.g.,(V_(BUS_A)) and the USB-C voltage bus 324 (e.g., (V_(BUS_C)).Alternatively, the initial inrush of current (Current A) may occur dueto a difference in voltage potential between the USB-C voltage bus 324(e.g., (V_(BUS_C)) and any other device and/or host connected to theUSB-C female connector 302 (e.g., an additional USB-C compatibledevice). The voltage bus capacitor 316 stores energy proportional to thecurrent conducting through it (Current B). The current (e.g., Current B)conducting through the voltage bus capacitor 316 is generated from theinitial inrush of current (Current A).

The example system capacitor 318 is a two terminal electrical componentthat stores energy in an electric field. In examples disclosed herein,the system capacitor 318 includes a capacitance predesignated by theUSB-C compatible device manufacturer (e.g., 100 microfarads, 200microfarads, 600 microfarads, etc.). The example system capacitor 318 iscoupled to the power supply 322. In examples disclosed herein, thesystem capacitor 318 is pre-charged to a voltage potential that willreverse bias the parasitic body diode 314. The parasitic body diode 314conducts when the voltage drop across the parasitic body diode 314(e.g., voltage drop from the USB-C main voltage bus 324 to the systemnode 326) satisfies the conduction threshold voltage (e.g., a thresholdvoltage of 0.7 volts).

The example controller 320 is coupled to the power supply 322, theblocking transistor 306, and the USB-C female connector 302. Thecontroller 320 may be implemented by one or more integrated circuits,logic circuits, microprocessors, graphics processing units (GPUs),digital signal processors (DSPs), or controllers from any desired familyor manufacturer. Other examples disclosed herein include the controller320 integrated within the device housing the USB-C female connector 302(e.g., the processor within a personal computer housing a USB-C femaleconnector 302). Additionally or alternatively, the controller 320 may beimplemented externally from the device housing the USB-C femaleconnector 302 (e.g., a personal computer housing a USB-C femaleconnector) in one or more integrated circuits, logic circuits,microprocessors, GPUs, DSPs, or controllers from any desired family ormanufacturer.

The controller 320 sends a turn on and/or off signal to the blockingtransistor 306. Additionally, the controller 320 sends a trigger signal(e.g., PWM signal) to the power supply 322 indicating whether or not topre-charge the system capacitor 318. In some examples disclosed herein,the turn on and/or off signal sent to the blocking transistor 306 may bethe same signal sent to the power supply 322. In examples disclosedherein, the controller 320 is connected to the USB-C female connector302 to obtain a reference value indicative of whether or not a device isattached (e.g., connected) or unattached (e.g., not connected) to theUSB-C female connector 302. For example, if no device is connected, thereference value may be indicative of no connection (e.g., the referencevalue may be zero). The controller 320 may be connected to a pin on theUSB-C female connector 302 such as the configuration channel pin;however, any other method of connecting the controller 320 to the USB-Cfemale connector 302 may be used.

The example state machine 321 is located in the controller 320. Theexample state machine 321 is any device that obtains and stores thestatus (e.g., state) of the reference value at the USB-C femaleconnector 302. Furthermore, in response to the state of the referencevalue obtained from the USB-C female connector 302, the state machine321 may generate commands to be sent to the blocking transistor 306and/or the power supply 322. Additionally, the state machine 321 mayserve as a communication link to the device connected to the USB-Cfemale connector 302 (e.g., the USB-A device 304) to negotiate a newcontract of operation. Example contracts of operation include indicatingwhich device (e.g., the device housing the USB-C schematic 300 or theUSB-A device 304) is to supply and/or consume power. The state machine321 may be implemented using hardware such as a logic circuit, software,or any combination of hardware and/or software.

The example power supply 322 is coupled to the controller 320 and thesystem node 326. The system node 326 is the node where the systemcapacitor 318 is coupled to the current terminal 312 (e.g., drainterminal) of the blocking transistor 306. The example power supply 322is included in the USB-C compatible device (e.g., the device whichincludes the USB-C female connector). In some examples disclosed herein,the power supply 322 may be a power converter (e.g., buck converter,boost converter, buck-boost converter, etc.), a battery, a switched modepower supply, and/or transformer. The power supply 322 may beimplemented externally to the USB-C schematic 300 (e.g., USB-C femaleconnector 302, blocking transistor 306, voltage bus capacitor 316,system capacitor 318, and/or the controller 320).

The power supply 322 is controlled by the controller 320 through aseries of signals and/or commands. Example signals and/or commands maybe generated using a digital-to-analog converter (DAC), an array ofswitches and/or transistors, and/or a control line. In some examplesdisclosed herein, the power supply 322 operates continuously,periodically, aperiodically and/or based on a trigger. In examplesdisclosed herein, the trigger is generated by the controller 320. Otherexamples disclosed herein may include a power supply 322 utilizingalternating current (AC) (e.g., an alternating current to direct currentpower converter, alternating current to alternating current powerconverter, alternating current transformer).

The voltage at the system node 326 is equivalent to the magnitude of thevoltage drop across the system capacitor 318. In order to reverse biasthe parasitic body diode 314, the voltage drop from the system node 326to the USB-C main voltage bus 324 should be less than the parasitic bodydiode 314 conduction threshold (e.g., 0.7 volts). The exampleillustrated in FIG. 3 includes a five-volt USB-A device 304, thus, thevoltage at the USB-C main voltage bus 324 is five volts. Furthermore, inthe example disclosed in FIG. 3 , to reverse bias the parasitic bodydiode 314, the voltage at the system node 326 (e.g., voltage across thesystem capacitor 318) is pre-charged to a voltage potential greater thanthe voltage at the USB-C main voltage bus 324 minus the conductionthreshold (e.g., pre-charge the system capacitor 318 to a voltagepotential greater than 4.3 volts). Examples disclosed herein are notlimited to specific voltage magnitudes. Furthermore, examples disclosedherein include pre-charging the system capacitor 318 to any voltagemagnitude that can reverse bias the parasitic component(s) (e.g., theparasitic body diode 314) in the blocking transistor 306. Examplesdisclosed herein include pre-charging the system capacitor 318 to avoltage potential that ensures the conduction threshold of the parasiticbody diode 314 is not satisfied. The system capacitor 318 may bepre-charged by sending a trigger to the power supply 322, thereforenotifying the power supply 322 to supply power to the system capacitor318. In some examples disclosed herein, power may be supplied as avoltage from the power supply 322.

The ground node 328 provides a reference voltage for the USB-C schematic300. In the illustration depicted in FIG. 3 the ground node 328 is achassis ground; however, they manner in which the USB-C schematic 300 isgrounded may vary. For example, the ground node 328 may be earth ground,analog ground, digital ground, or any other voltage reference.

FIG. 4 is a block diagram 400 of further detail of the examplecontroller 320 of FIG. 3 that may be used in combination the USB-Cschematic 300 of FIG. 3 . The example controller 320 includes the statemachine 321 of FIG. 3 , an example control signal generator 402, and anexample negotiator 404. The state machine 321, control signal generator402, and negotiator 404 are communicatively connected. For the purposesof driving the power supply 322 and/or blocking transistor 306, thecontroller 320 receives a reference value from a communication pinlocated in the USB-C female connector 302. An example communication pinmay be any pin located in the USB-C female connector capable ofcommunicating the state of connection (e.g., whether a device isconnected or not connected) to the controller 320. The controller 320produces two outputs that trigger the power supply 322 and the blockingtransistor 306. The number of inputs and produced outputs in thecontroller 320 may vary.

The example state machine 321 receives the reference value from theUSB-C female connector 302. The state machine 321 communicates with thecontrol signal generator 402 and the negotiator 404 to serve as acommunication link. The state machine 321 determines if the referencevalue received from the USB-C female connector 302 is indicative of aconnected device or not. Additionally, after determining if thereference signal indicates a connected device or not, the state machine321 communicates the indication of the result (e.g., whether a device isconnected or not connected to the USB-C female connector 302) to thecontrol signal generator 402. For example, if the state machine 321determines that a device is connected to the USB-C female connector 302,an indication of the connected device is communicated to the controlsignal generator 402. Likewise, if the state machine 321 determines thata device is not connected to the USB-C female connector 302, anindication the unattached connection is communicated to the controlsignal generator 402.

The example control signal generator 402 communicates with the statemachine 321 to receive the indication of the result (e.g., whether adevice is connected or not connected to the USB-C female connector 302).The control signal generator 402 generates a control signal in responseto the indication received to turn on and/or turn off the power supply322 and/or the blocking transistor 306. For example, if the controlsignal generator 402 receives an indication from the state machine 321of a device connected to the USB-C female connector 302, the controlsignal generator 402 may generate a signal to turn on the blockingtransistor 306 and a signal to modify the operation of the power supply322. Likewise, if the control signal generator 402 receives anindication from the state machine 321 of no device connected to theUSB-C female connector 302, the control signal generator 402 maygenerate a signal to turn off the blocking transistor 306 and a signalto change the operation of the power supply 322 to pre-charge the systemcapacitor 318 of FIG. 3 . In other examples, the polarity of theindication from the state machine 321 may alter the actions of thecontrol signal generator 402. In some examples disclosed herein, thecontrol signal generator 402 generates the control signal in response toan indication received from the negotiator 404 of a negotiation status.

The example negotiator 404 communicates with the state machine 321 andthe example control signal generator 402. The negotiator 404 facilitatescommunication with a device connected to the USB-C female connector 302.In examples disclosed herein, the negotiator 404 responds to thedetermination from the state machine 321 of a connected device bynegotiating a contract with the connected device to have the connecteddevice act as a sink. In such examples, after the negotiator 404negotiates the contract with the connected device, the controller 320enters in a source mode (e.g., the controller 320 is facilitating thesourcing of power to the connected device).

The controller 320 of the illustrated example is hardware. For example,the controller 320 can be implemented by one or more integratedcircuits, logic circuits, microprocessors, GPUs, DSPs, or controllersfrom any desired family or manufacturer. The hardware controller 320 maybe a semiconductor based (e.g., silicon based) device. The processorplatform can be, for example, a server, a personal computer, aworkstation, a dock, a monitor, a self-learning machine (e.g., a neuralnetwork), a mobile device (e.g., a cell phone, a smart phone, a tablet),a personal digital assistant (PDA), an Internet appliance, a DVD player,a CD player, a digital video recorder, a Blu-ray player, a gamingconsole, a personal video recorder, a set top box, a headset or otherwearable device, or any other type of computing device. In otherexamples disclosed herein, the controller 320 may be implemented as anembedded system in which the state machine 321 and/or the control signalgenerator 402 may be implemented as software and/or hardware.

In the illustrated example of FIG. 4 , the controller 320 and theblocking transistor 306 are implemented together in an integratedcircuit (e.g., on a chip, etc.). In FIG. 4 , the controller 320 and theblocking transistor 306 are configured to be connected to the USB-Cfemale connector 302, the system capacitor 318, and to the power supply322. In other examples disclosed herein, the state machine 321, thecontrol signal generator 402, and/or the negotiator 404 may beimplemented internally or externally from the controller 320. Likewise,in other examples disclosed herein, the controller 320 and the blockingtransistor 306 may be implemented in separate IC's.

FIG. 5 illustrates a dual-port device 500 coupled to an examplecontroller 530 to control an example variable power supply 528. Amongvarious components depicted in FIG. 5 , the dual-port device 500illustrates includes two USB-C female connectors (504, 516).Furthermore, illustrated in FIG. 5 is a variable power supply 528coupled to the example system capacitor 502. The example systemcapacitor 502 is coupled in series with the blocking transistor 506 andthe USB-C female connector 504. Additionally, the system capacitor 502is coupled in series with the blocking transistor 518 and the USB-Cfemale connector 516. The first blocking transistor 506 is coupled tothe first USB-C female connector 504, and the second blocking transistor518 is coupled to the second USB-C female connector 516. The exampledual-port device 500 includes an example controller 530 and an examplestate machine 531. In examples disclosed herein. the controller 530 maybe implemented as the controller 320 of FIG. 3 and the state machine 531may be implemented as the state machine 321 of FIG. 3 .

The first USB-C female connector 504 is coupled to the first blockingtransistor 506. The first USB-C female connector 504 is located on ahost device (e.g., personal computer, laptop, dock); however, the firstUSB-C female connector 504 may be located on other devices as well(e.g., peripheral devices). The first USB-C female connector 504includes full duplex connection capabilities (e.g., abilitysimultaneously communicate host-to-device or device-to-host). A fullduplex connector (e.g., the first USB-C female connector 504) is aconnector that allows for the transmission of data in two directions,simultaneously. The full duplex USB-C connector (e.g., the first USB-Cfemale connector 504) enables compatible electronic devices to crosstalk, supply power, and/or consume power, simultaneously. Additionally,in some examples disclosed herein, the first USB-C female connector 504is a universal serial bus type-c power delivery compatible connectorthat is compatible with universal serial bus type-c power deliveryapplications.

Additionally, the first USB-C female connector 504 supports thespecifications supported by USB-A (e.g., USB 1.0, USB 1.1, USB 2.0, USB3.0), along with the Universal Serial Bus 3.1 (USB 3.1) and UniversalSerial Bus Power Deliver (USB PD) specifications. The first USB-C femaleconnector 504 supports all legacy specifications supported by the USB-Astandard.

The example first blocking transistor 506 is an n-channelmetal-oxide-semiconductor field-effect transistor (NMOS). In otherexamples, the first blocking transistor 506 may be an p-channelmetal-oxide-semiconductor field-effect transistor (PMOS) or any otherswitching device. The first blocking transistor 506 includes threecurrent terminals (e.g., gate terminal 508, current terminal 510 (e.g.,source terminal), and current terminal 512 (e.g., drain terminal)) and afirst parasitic body diode 514. In the example depicted in FIG. 5 , thefirst blocking transistor 506 includes a gate terminal 508 coupled to acontroller 530.

The example gate terminal 508 of the first blocking transistor 506receives an input signal from the example controller 530. The inputsignal received at the gate terminal 508 of the first blockingtransistor 506 may be a pulse width modulation (PWM) signal. The PWMsignal is a periodic signal having a frequency with a respective on-timeand off time.

The example current terminal 510 (e.g., source terminal) of the firstblocking transistor 506 is coupled to the first USB-C female connector504. The node shared by the current terminal 510 (e.g., source terminal)and the first USB-C female connector 504 is coupled to the controller530. The current terminal 512 (e.g., drain terminal) of the firstblocking transistor 506 is coupled to the example system capacitor 502and the variable power supply 528.

Additionally, the first blocking transistor 506 includes a first exampleparasitic body diode 514. The first parasitic body diode 514 is aparasitic diode that conducts current when a voltage drop between theanode (e.g., current terminal 510) and the cathode (e.g., currentterminal 512) exceeds a conduction threshold. In some examples, theconduction threshold is 0.7 volts; however, the conduction threshold isnot limited to any value disclosed herein. The inherent first parasiticdiode 514 may conduct a parasitic current while the first blockingtransistor 506 is not conducting. For example, the current conductingthrough the current terminal 512 (e.g., drain terminal) to the currentterminal 510 (e.g., source terminal) is zero amperes when the firstblocking transistor 506 is not conducting, and the current conductingthrough the first parasitic body diode 514 may be one microampere. Otherexamples disclosed herein include a current conducting through theparasitic body diode 514, while the first blocking transistor 506 isconducting or not conducting, of any numerical ampere value (e.g., oneampere, 5 amperes, 10 amperes). The conduction of current through thefirst parasitic body diode 514 when the first blocking transistor 506 isnot conducting may cause damage to the USB-C device (e.g., the devicethat includes the dual-port device 500) or the USB-A source (e.g., thedevice connected to the first USB-C female connector 504).

The second USB-C female connector 516 is coupled to the second blockingtransistor 518. The second USB-C female connector 516 is located on ahost device (e.g., personal computer, laptop, dock); however, the secondUSB-C female connector 516 may be located on other devices as well(e.g., peripheral devices). The second USB-C female connector 516includes full duplex connection capabilities (e.g., abilitysimultaneously communicate host-to-device or device-to-host). A fullduplex connector (e.g., the second USB-C female connector 516) is aconnector that allows for the transmission of data in two directions,simultaneously. The full duplex USB-C connector (e.g., the second USB-Cfemale connector 516) enables compatible electronic devices to crosstalk, supply power, and/or consume power, simultaneously. Additionally,in some examples disclosed herein, the second USB-C female connector 504is a universal serial bus type-c power delivery compatible connectorthat is compatible with universal serial bus type-c power deliveryapplications.

Additionally, the second USB-C female connector 516 supports thespecifications supported by USB-A (e.g., USB 1.0, USB 1.1, USB 2.0, USB3.0), along with the Universal Serial Bus 3.1 (USB 3.1) and UniversalSerial Bus Power Deliver (USB PD) specifications. The second USB-Cfemale connector 516 supports all legacy specifications supported by theUSB-A standard.

The example second blocking transistor 518 is an n-channelmetal-oxide-semiconductor field-effect transistor (NMOS). In otherexamples, the second blocking transistor 518 may be an p-channelmetal-oxide-semiconductor field-effect transistor (PMOS) or any otherswitching device. The second blocking transistor 518 includes threecurrent terminals (e.g., gate terminal 520, current terminal 522, andcurrent terminal 524) and a second parasitic body diode 526. In theexample depicted in FIG. 5 , the second blocking transistor 518 includesa gate terminal 520 coupled to the controller 530.

The example gate terminal 520 of the second blocking transistor 518receives an input signal from the example controller 530. The inputsignal received at the gate terminal 520 of the second blockingtransistor 518 may be a pulse width modulation (PWM) signal. The PWMsignal is a periodic signal having a frequency with a respective on-timeand off time.

The example current terminal 522 (e.g., source terminal) of the secondblocking transistor 518 is coupled to the second USB-C female connector516. The node shared by the current terminal 522 (e.g., source terminal)and the second USB-C female connector 516 is coupled to the controller530. The current terminal 524 (e.g., drain terminal) of the secondblocking transistor 518 is coupled to the example system capacitor 502and the variable power supply 528.

Additionally, the second blocking transistor 518 includes a secondexample parasitic body diode 526. The second parasitic body diode 526 isa parasitic diode that conducts current when a voltage drop between theanode (e.g., current terminal 522) and the cathode (e.g., currentterminal 524) exceeds a conduction threshold. In some examples, theconduction threshold is 0.7 volts; however, the conduction threshold isnot limited to any value disclosed herein. The inherent second parasiticdiode 526 may conduct a parasitic current while the second blockingtransistor 518 is not conducting. For example, the current conductingthrough the current terminal 524 (e.g., drain terminal) to the currentterminal 522 (e.g., source terminal) is zero amperes when the secondblocking transistor 506 is not conducting, and the current conductingthrough the second parasitic body diode 526 may be one microampere.Other examples disclosed herein include a current conducting through thesecond parasitic body diode 526, while the second blocking transistor518 is conducting or not conducting, of any numerical ampere value(e.g., one ampere, 5 amperes, 10 amperes). The conduction of currentthrough the second parasitic body diode 526 when the second blockingtransistor 518 is not conducting may cause damage to the USB-C device(e.g., the device that includes the dual-port device 500) or the USB-Asource (e.g., the device connected to the second USB-C female connector516).

The example variable power supply 528 is coupled to the controller 530and the node that includes the system capacitor 502 and the currentterminals 512, 524 of the first and second blocking transistors 506,518. The example variable power supply 528 is included in the USB-Ccompatible device (e.g., the device which includes the USB-C femaleconnectors 504, 516). In some examples disclosed herein, the variablepower supply 528 may be a power converter (e.g., buck converter, boostconverter, buck-boost converter, etc.), a battery, a switched mode powersupply, and/or transformer. Additionally, the variable power supply 528is controlled by the controller 530 through a series of signals and/orcommands. Example signals and/or commands may be generated using adigital-to-analog converter (DAC), an array of switches and/ortransistors, and/or a control line. In some examples disclosed herein,the variable power supply 528 operates continuously, periodically,aperiodically and/or based on a trigger. In examples disclosed herein,the trigger is generated by the controller 530. Other examples disclosedherein may include a variable power supply 528 utilizing alternatingcurrent (AC) (e.g., an alternating current to direct current powerconverter, alternating current to alternating current power converter,alternating current transformer). Examples disclosed herein includepre-charging the system capacitor 502 to any voltage magnitude that canreverse bias the parasitic component(s) (e.g., the parasitic bodydiode(s) 514 and/or 526) in the blocking transistor(s) 506 and/or 518.Examples disclosed herein include pre-charging the system capacitor 502to a voltage potential that ensures the conduction threshold of theparasitic body diode(s) 514 and/or 526 is not satisfied. The systemcapacitor 502 may be pre-charged by sending a trigger to the variablepower supply 528, therefore notifying the variable power supply 528 tosupply power to the system capacitor 502. In some examples disclosedherein, power may be supplied through a voltage from the variable powersupply 528.

The example controller 530 of FIG. 5 includes the state machine 321 ofFIG. 3 , the control signal generator 402, and the negotiator 404 ofFIG. 4 . The example controller 530 is coupled to the variable powersupply 528, the blocking transistors 506, 518, and the USB-C femaleconnectors 504, 516. The controller 530 may be implemented by one ormore integrated circuits, logic circuits, microprocessors, graphicsprocessing units (GPUs), digital signal processors (DSPs), orcontrollers from any desired family or manufacturer. Other examplesdisclosed herein include the controller 530 integrated within the devicehousing the dual USB-C female connectors 504, 516 (e.g., the processorwithin a personal computer housing the dual USB-C female connectors 504,516). Additionally or alternatively, the controller 530 may beimplemented externally from the device housing the dual USB-C femaleconnector 504, 516 (e.g., a personal computer housing a USB-C femaleconnector) in one or more integrated circuits, logic circuits,microprocessors, GPUs, DSPs, or controllers from any desired family ormanufacturer.

In the example depicted in FIG. 5 , the controller 530 sends a turn onand/or off signal to the blocking transistors 506, 518 (lines 532, 534).Additionally, the controller 530 sends a trigger signal (e.g., PWMsignal) (line 536) to the variable power supply 528 indicating whetheror not to pre-charge the system capacitor 502. In examples disclosedherein, the controller 530 is connected to the USB-C female connectors504, 516 to obtain reference values indicative of whether or not adevice is attached (e.g., connected) or unattached (e.g., not connected)to the USB-C female connectors 504, 516. For example, if no device isconnected to the USB-C female connector 504, the reference value may beindicative of no connection (e.g., the reference value may be zero) tothe USB-C female connector 504. The controller 530 may be connected to apin on the USB-C female connectors 504, 516 such as the configurationchannel pin; however, any other method of connecting the controller 530to the USB-C female connectors 504, 516 may be used.

The example state machine 531 is located in the controller 530. Theexample state machine 531 is any device that obtains and/or stores thestatus (e.g., state) of the reference value at the USB-C femaleconnectors 504, 516. Furthermore, in response to the state of thereference values obtained from the USB-C female connectors 504, 516, thestate machine 531 may generate commands to be sent to the blockingtransistors 506, 518 (lines 532, 534) and/or the variable power supply528 (line 536). Additionally, the state machine 531 may serve as acommunication link to the device(s) connected to the USB-C femaleconnectors 504, 516 to negotiate a new contract of operation. Examplecontracts of operation include indicating which device (e.g., the devicehousing the USB-C female connectors 504, 516 or the USB-A deviceconnected to the USB-C female connectors 504, 516) is to supply and/orconsume power. The state machine 531 may be implemented using hardwaresuch as a logic circuit, software, or any combination of hardware and/orsoftware.

The controller 530 of the illustrated example is hardware. For example,the controller 530 can be implemented by one or more integratedcircuits, logic circuits, microprocessors, GPUs, DSPs, or controllersfrom any desired family or manufacturer. The hardware controller 530 maybe a semiconductor based (e.g., silicon based) device. The processorplatform can be, for example, a server, a personal computer, aworkstation, a dock, a monitor, a self-learning machine (e.g., a neuralnetwork), a mobile device (e.g., a cell phone, a smart phone, a tablet),a personal digital assistant (PDA), an Internet appliance, a DVD player,a CD player, a digital video recorder, a Blu-ray player, a gamingconsole, a personal video recorder, a set top box, a headset or otherwearable device, or any other type of computing device.

FIG. 6 is a graphical illustration 600 of various signals of the examplesystem of FIG. 3 during operation. The graphical illustration 600includes a state indication of the USB-C female connector 302 (segments606, 608, 610), a gate terminal 308 of FIG. 3 signal, line 612, avoltage potential across the system capacitor 318 of FIG. 3 , line 614,and a voltage potential at the current terminal (e.g., source terminal)310 of FIG. 3 , line 616.

Initially, the state of the USB-C female connector 302, segment 606, isunattached (e.g., not connected). Line 612 for the gate terminal 308 ofthe blocking transistor 306 is low (e.g., off), indicating to notconduct. Likewise, the voltage potential across the system capacitor318, line 614, is pre-charged. Illustrated in FIG. 6 , the magnitude ofthe voltage of line 614 is six volts; however, the magnitude of thevoltage of line 614 is not limited to any specific value.

During times 601 and 602, the state of the USB-C female connector 302,segment 608, is attached. Initially, illustrated in FIG. 6 , the deviceattached to the USB-C female connector 302 may act as a source. Thiscauses the voltage potential at the current terminal (e.g., sourceterminal) 310, line 616, to increase to around 5 volts.

During times 602 and 603, the controller 320 of FIG. 3 negotiates withthe device attached (e.g., connected) to the USB-C female connector 302to indicate to supply power. As a result of this negotiation, the deviceattached (e.g., connected) to the USB-C female connector 302 acts as asink. The voltage across the system capacitor 318, line 614, begins todecrease due to the change in contract to supply power. Alternatively,the voltage across the system capacitor 318, line 614, may increase toany numerical voltage magnitude (e.g., five volts, ten volts, twentyvolts) to supply power to the device connected to the USB-C femaleconnector 302. During times 603 and 604, the signal to the gate terminal308 is high (e.g., indicating to turn on the blocking transistor 306),line 612. Likewise, the voltage potential across the system capacitor318 is equivalent to the voltage potential at the current terminal(e.g., source terminal) 310. The device connected to the USB-C femaleconnector 302 is acting as a sink, segment 610, therefore consumingpower.

FIG. 7 is a state diagram 700 representative of example operating statesin which the controller 320, 530 of FIG. 3, 4 , or 5 may operate. Whenin an example first state 702, the controller 320, 530 of FIG. 3, 4 , or5 is in an example unattached mode (e.g., not connected). In the examplefirst state 702, the controller 320 of FIG. 3, 4 , or 5 generates asignal that indicates to operate the power supply (e.g., the powersupply 322 of FIG. 3 and/or the variable power supply 528 of FIG. 5 ) tocharge the system capacitor (e.g., the system capacitor 318 of FIG. 3and/or the system capacitor 502 of FIG. 5 ) to a threshold voltage. Oncea device is attached (e.g., connected) to the USB-C female connector(e.g., the USB-C female connector 302, 504, 516), the first operatingcondition 704 is satisfied.

In the illustrated example of FIG. 7 , in response to a device beingattached to the USB-C female connector (e.g., the USB-C female connector302, 504, 516), the controller (e.g., the controller 320 or thecontroller 530) enters an example second state 706, a sink mode. In theexample second state 706, a negotiator (e.g., the negotiator 404)initiates negotiation with the attached (e.g., connected) device. Inexamples disclosed herein, the negotiation is initiated to determinewhen to source power. When the negotiation between the attached (e.g.,connected) device and the controller (e.g., the controller 320 or thecontroller 530) is complete, the example second operating condition 708is satisfied. Examples in which the negotiation completes includes thedetermination for the controller to source power to the connecteddevice.

In the illustrated example of FIG. 7 , in response to the negotiationbetween the attached (e.g., connected) device and the controller (e.g.,the controller 320 or the controller 530) being complete, the controller(e.g., the controller 320 or the controller 530) enters an example thirdstate 710, a source mode. In the example third state 710, the controller(e.g., the controller 320 or the controller 530) modifies the powersupply (e.g., the power supply 322 of FIG. 3 and/or the variable powersupply 528 of FIG. 5 ) to supply power to attached device and turns onblocking transistor (e.g., the blocking transistor 306 of FIG. 3 , thefirst blocking transistor 506 of FIG. 5 , or the second blockingtransistor 518 of FIG. 5 ). When the device becomes unattached (e.g.,not connected), the example third operating condition 712 is satisfiedand the controller (e.g., the controller 320 or the controller 530)enters the example first state 702.

While an example manner of implementing the controller of FIGS. 4 isillustrated in FIGS. 3 and 5 , one or more of the elements, processesand/or devices illustrated in FIGS. 3 and 5 may be combined, divided,re-arranged, omitted, eliminated and/or implemented in any other way.Further, the example state machine 321, 531, the example control signalgenerator 402, the example negotiator 404 and/or, more generally, theexample controller 320 of FIG. 3 or the controller 530 of FIG. 5 may beimplemented by hardware, software, firmware and/or any combination ofhardware, software and/or firmware. Thus, for example, any of theexample the example state machine 321, 531, the example control signalgenerator 402, the example negotiator 404 and/or, more generally, theexample controller 320, 530 could be implemented by one or more analogor digital circuit(s), logic circuits, programmable processor(s),programmable controller(s), graphics processing unit(s) (GPU(s)),digital signal processor(s) (DSP(s)), application specific integratedcircuit(s) (ASIC(s)), programmable logic device(s) (PLD(s)) and/or fieldprogrammable logic device(s) (FPLD(s)). When reading any of theapparatus or system claims of this patent to cover a purely softwareand/or firmware implementation, at least one of the example, the examplestate machine 321, 531, the example control signal generator 402, theexample negotiator 404 and/or, more generally, the example controller320 of FIG. 3 or the controller 530 of FIG. 5 is/are hereby expresslydefined to include a non-transitory computer readable storage device orstorage disk such as a memory, a digital versatile disk (DVD), a compactdisk (CD), a Blu-ray disk, etc. including the software and/or firmware.Further still, the example controller of FIGS. 3 and 5 may include oneor more elements, processes and/or devices in addition to, or insteadof, those illustrated in FIG. 4 , and/or may include more than one ofany or all of the illustrated elements, processes and devices. As usedherein, the phrase “in communication,” including variations thereof,encompasses direct communication and/or indirect communication throughone or more intermediary components, and does not require directphysical (e.g., wired) communication and/or constant communication, butrather additionally includes selective communication at periodicintervals, scheduled intervals, aperiodic intervals, and/or one-timeevents.

A flowchart representative of example hardware logic, machine readableinstructions, hardware implemented state machines, and/or anycombination thereof for implementing the controller of FIGS. 3-5 isshown in FIG. 8 . The machine readable instructions may be an executableprogram or portion of an executable program for execution by a computerprocessor such as the controller (e.g., the controller 320 or thecontroller 530) discussed above in connection with FIGS. 3-5 . Theprogram may be embodied in software stored on a non-transitory computerreadable storage medium such as a CD-ROM, a floppy disk, a hard drive, aDVD, a Blu-ray disk, or a memory associated with the controller (e.g.,the controller 320 or the controller 530), but the entire program and/orparts thereof could alternatively be executed by a device other than thecontroller (e.g., the controller 320 or the controller 530) and/orembodied in firmware or dedicated hardware. Further, although theexample program is described with reference to the flowchart illustratedin FIG. 8 , many other methods of implementing the example controller320, 530 may alternatively be used. For example, the order of executionof the blocks may be changed, and/or some of the blocks described may bechanged, eliminated, or combined. Additionally or alternatively, any orall of the blocks may be implemented by one or more hardware circuits(e.g., discrete and/or integrated analog and/or digital circuitry, anFPGA, an ASIC, a comparator, an operational-amplifier (op-amp), a logiccircuit, etc.) structured to perform the corresponding operation withoutexecuting software or firmware.

As mentioned above, the example processes of FIG. 8 may be implementedusing executable instructions (e.g., computer and/or machine readableinstructions) stored on a non-transitory computer and/or machinereadable medium such as a hard disk drive, a flash memory, a read-onlymemory, a compact disk, a digital versatile disk, a cache, arandom-access memory and/or any other storage device or storage disk inwhich information is stored for any duration (e.g., for extended timeperiods, permanently, for brief instances, for temporarily buffering,and/or for caching of the information). As used herein, the termnon-transitory computer readable medium is expressly defined to includeany type of computer readable storage device and/or storage disk and toexclude propagating signals and to exclude transmission media.

“Including” and “comprising” (and all forms and tenses thereof) are usedherein to be open ended terms. Thus, whenever a claim employs any formof “include” or “comprise” (e.g., comprises, includes, comprising,including, having, etc.) as a preamble or within a claim recitation ofany kind, it is to be understood that additional elements, terms, etc.may be present without falling outside the scope of the correspondingclaim or recitation. As used herein, when the phrase “at least” is usedas the transition term in, for example, a preamble of a claim, it isopen-ended in the same manner as the term “comprising” and “including”are open ended. The term “and/or” when used, for example, in a form suchas A, B, and/or C refers to any combination or subset of A, B, C such as(1) A alone, (2) B alone, (3) C alone, (4) A with B, (5) A with C, (6) Bwith C, and (7) A with B and with C. As used herein in the context ofdescribing structures, components, items, objects and/or things, thephrase “at least one of A and B” is intended to refer to implementationsincluding any of (1) at least one A, (2) at least one B, and (3) atleast one A and at least one B. Similarly, as used herein in the contextof describing structures, components, items, objects and/or things, thephrase “at least one of A or B” is intended to refer to implementationsincluding any of (1) at least one A, (2) at least one B, and (3) atleast one A and at least one B. As used herein in the context ofdescribing the performance or execution of processes, instructions,actions, activities and/or steps, the phrase “at least one of A and B”is intended to refer to implementations including any of (1) at leastone A, (2) at least one B, and (3) at least one A and at least one B.Similarly, as used herein in the context of describing the performanceor execution of processes, instructions, actions, activities and/orsteps, the phrase “at least one of A or B” is intended to refer toimplementations including any of (1) at least one A, (2) at least one B,and (3) at least one A and at least one B.

FIG. 8 is a flowchart 800 representative of machine readableinstructions that may be executed to implement the controller 320, 530of FIGS. 3-5 . Initially, the controller 320 determines the state offrom the USB-C female connector 302, 504, or 506 (Block 810). Inexamples disclosed herein, the controller 320 may obtain a referencevalue and determine the state of the USB-C female connector 302, 504, or506 (Block 810). The state machine 321, 531 in the controller 320analyzes the state of the reference signal to determine if a sourcedevice (e.g., USB-A device 304 or a second USB-C compatible device isplugged in, connected to, attached, and/or communicating with the USB-Cfemale connector 302 and/or the device which houses the USB-C femaleconnector 302) is attached. (Block 820).

If the reference value obtained by the state machine 321, 531 indicatesa source device is attached (e.g., device is not plugged in, connectedto, attached, and/or communicating with the USB-C female connector 302,504, 516 and/or the device which houses the USB-C female connector 302,504, 516) and, thus, the controller 320, 530 is operating in sink mode,the control signal generator 402 generates a signal that indicates tooperate the power supply 322 and/or the variable power supply 528 tocharge the system capacitor 318, 502 (Block 830). In some examples, thestate machine 321, 531 may generate the signal to operate the powersupply 322 and/or the variable power supply 528 to charge the systemcapacitor 318, 502. Additionally, the control signal generator 402transmits the signal to the power supply 322 and/or the variable powersupply 528 (Block 835). In response to the control signal generator 402transmitting the signal to the power supply 322 and/or the variablepower supply 528, the power supply 322 and/or the variable power supply528 charges the system capacitor 318, 502 to a threshold voltage (e.g.,a voltage potential that ensures the parasitic body diode(s) 314, 514,526 is/are reverse biased) (Block 840). The negotiator 404 determines ifthe controller 320, 530 is operating in source mode (Block 845). Inexamples disclosed herein, the negotiator 404 determines the controller320, 530 is operating in source mode in response to a negotiation beingcomplete to a connected device. Additionally or alternatively, thecontroller 320, 530 may execute the control of block 845 if the systemcapacitor 318, 502 is charged to a voltage potential that satisfies thethreshold and ensures the parasitic body diode(s) 314, 514, 526 is/arereverse biased. If the controller 320, 530 determines the systemcapacitor 318, 502 is not yet charged to a voltage potential thatensures the parasitic body diode(s) 314, 514, 526 is/are reverse biased,the control signal generator 402 continues to generate a signal tooperate the power supply 322 and/or the variable power supply 528 tocharge the system capacitor 318, 502 (Block 840). The example processesillustrated above reducing the inrush current experienced by theparasitic body diode(s) 314, 514, or 526.

If the controller 320, 530 determines that the system capacitor 318, 502is charged to a voltage potential that ensures the parasitic bodydiode(s) 314, 514, 526 is/are reverse biased, the controller 320, 530then determines whether or not to continue operating (Block 870).Instance in which the controller 320, 530 is to cease operating includeloss of power or manual shut-off. If the controller 320, 530 is tocontinue operating, the state machine 321, 531 continues to obtain areference value from the USB-C female connector (Block 810).

If the reference value obtained by the state machine 321, 521 indicatesa source device is attached (e.g., a device is plugged in, connected to,attached, and/or communicating with the USB-C female connector 302, 504,516 and/or the device which houses the USB-C female connector 302, 504,516) and, thus, the controller 320, 530 is operating in source mode, thestate machine 321, 531 indicates to the control signal generator 402 togenerate and/or transmit a signal to modify the power supply 322 and/orthe variable power supply 528 to supply power to the connected device(Block 850). In examples disclosed herein, control operates the functionof block 850 in response to a negotiation between the attached deviceand the controller 320, 530 being complete. Additionally, the controlsignal generator 402 generates a signal to allow the blocking transistor306, 506, 518 to conduct current (Block 860). The controller 320, 530then determines whether or not to continue operating (Block 870).Instance in which the controller 320, 530 is to cease operating includeloss of power or manual shut-off. If the controller 320, 530 is tocontinue operating, the state machine 321, 531 continues to obtain areference value from the USB-C female connector (Block 810).

From the foregoing, it will be appreciated that example methods,apparatus and articles of manufacture have been disclosed that reduceparasitic currents that occur in Universal Serial Bus Type-C circuitsand systems. The disclosed methods, apparatus and articles ofmanufacture improve the efficiency of using a computing device bypreventing harmful parasitic currents from conducting in a device.Furthermore, the disclosed methods, apparatus and articles ofmanufacture improve the efficiency of using a computing device byimproving the operating efficiency of Universal Serial Bus Type-Ccompatible devices by reducing exposure to harmful parasitic currents.The disclosed methods, apparatus and articles of manufacture areaccordingly directed to one or more improvement(s) in the functioning ofa computer.

Although certain example methods, apparatus and articles of manufacturehave been disclosed herein, the scope of coverage of this patent is notlimited thereto. On the contrary, this patent covers all methods,apparatus and articles of manufacture fairly falling within the scope ofthe claims of this patent.

What is claimed is:
 1. An apparatus comprising: a power supply having apower control input and having a power output; a single field effecttransistor (FET) having a source, a drain and a gate, wherein the sourceis connected to a voltage bus, and the drain is directly connected tothe power output; and a controller including a state machine and acontrol signal generator, wherein the controller is coupled to aconnector and to a power supply; wherein the state machine isconfigurable to provide an indication of a first state of the connector,and the control signal generator is configurable to provide a controlsignal to initiate the power supply charging a capacitor to a thresholdvoltage in response to the indication of the first state, and thecontrol signal generator is configurable to provide the control signaluntil a second state.
 2. The apparatus of claim 1, wherein thecontroller has a gate output, a connector input and a control output, inwhich the gate output is directly connected to the gate, the connectorinput is coupled to a controller terminal on the connector, and thecontrol output is coupled to the power control input.
 3. The apparatusof claim 1, wherein the single FET has a parasitic body diode with ananode directly connected to a protection terminal on a connector, and acathode directly connected to the power output.
 4. The apparatus ofclaim 3, further comprising a system capacitor directly connectedbetween the cathode and a ground terminal.
 5. The apparatus of claim 1,wherein the connector is a universal serial bus type-c connector.
 6. Theapparatus of claim 5, wherein the connector is a first universal serialbus connector, the controller is configured to be coupled to a secondconnector, and the second connector is a second universal serial busconnector.
 7. The apparatus of claim 6, wherein the control signal is afirst control signal, the state machine is further configured todetermine a third state of the second connector, and the control signalgenerator is further configured to, in response to an indication of thethird state of the second connector, provide a second control signal toinitiate the power supply charging the capacitor to the thresholdvoltage.
 8. The apparatus of claim 6, wherein the second connector iscompatible with universal serial bus type-c power delivery applications.9. The apparatus of claim 1, wherein the control signal generator isconfigured to, in response to the second state, provide a second controlsignal to initiate the power supply to supply power to a device.
 10. Theapparatus of claim 9, wherein the controller further includes anegotiator configured to negotiate a contract with the device toinitiate the power supply to supply power to the device.
 11. A systemcomprising: a power supply having a power control input and having apower output; a single transistor having a source, a drain and a gate,wherein the source is connected to a voltage bus, and the drain isdirectly connected to the power output and a capacitor; a controllercoupled to a connector, the power supply, and the single transistor,wherein the controller includes: a state machine configurable todetermine a state of a connection at the connector; and a control signalgenerator configurable to provide a signal to modify an operation of thepower supply in response to an indication from the state machine. 12.The system of claim 11, wherein the control signal generator generatesthe signal to modify the power supply to charge the capacitor inresponse to the indication being indicative of no devices beingconnected to the connector.
 13. The system of claim 12, wherein thecontrol signal generator provides the signal until a device is connectedto the connector and a contract is negotiated.
 14. The system of claim13, wherein the controller further includes a negotiator, and thecontrol signal generator provides a second signal to modify the powersupply to supply power to the device connected to the connector inresponse to the negotiator contracting with a device connected to theconnector.
 15. The system of claim 11, further including a universalserial bus type-a host connected to a universal serial bus type-a touniversal serial bus type-c adapter, wherein the universal serial bustype-a to universal serial bus type-c adapter is connected to theconnector.
 16. The system of claim 11, further including a secondtransistor having third and fourth current terminals, wherein the thirdcurrent terminal is coupled to a second connector, and the fourthcurrent terminal is coupled to the capacitor and the power supply. 17.The system of claim 16, wherein the state machine determines a secondstate of the second connector.
 18. The system of claim 11, wherein theconnector is a universal serial bus type-c connector, and the connectoris compatible with universal serial bus type-c power deliveryapplications.